Endocrine Abstracts

Objective: The aim of this study was to evaluate the influence of subclinical and overt hyperthyroidism on the chosen markers of endothelial function.

Material and methods: The groups studied consisted of 97 hyperthyroid subjects (51 with subclinical and 46 with overt hyperthyroidism) and 39 healthy controls matched for age, gender and body mass index. The following parameters were measured: TSH, FT3, FT4 (by MEIA), VCAM-1 (vascular cell adhesion molecule 1), ICAM-1 (intercellular adhesion molecule 1), von Willebrand factor (vWF) and PAI-1 (plasminogen activator inhibitor 1) (by ELISA). Statistical analysis was performed using the computer program STATISTICA 6.0. The local ethical committee aproved the study.

Results: Among hyperthyroid patients 71 had toxic goiter (42 with subclinical and 29 with overt hyperthyroidism) and 26 had Graves’ disease (9-subclinical, 17-overt hyperthyroidism). Significantly higher VCAM-1 levels were found in patients with overt and subclinical hyperthyroidism in comparison with the control group (1336.5+608.5 and 1168.9+508.4 vs 835.5+302.6 ng/ml, P<0.001 and P<0.001, respectively); vWF concentration was also significantly higher in patients with overt and subclinical hyperthyroidism than in the controls (P<0.001 and P<0.01, respectively), and in patients with overt hyperthyroidism in comparison with the subclinical group (P<0.01). The highest PAI-1 values were observed in patients with overt hyperthyridism (68.07 ng/ml, P<0.001 in comparison with subclinical hyperthyroidism and P<0.001 in comparison with the control group). There were not significant differences in ICAM-1 levels between the groups studied.

Conclusion: Our results suggest that endothelial dysfunction occurs in patients with overt as well as subclical hyperthyroidism.